There is a reason why JAGEX did not make dual wielding possible. First, you won't kill someone with dual weapons because they will be too powerful and the same goes to the other person if you were dual wielding because you are too powerful. Secondly, dual wielding would destroy the meaning of using a shield and will make the shield as useless as a bronze dagger, as you can wield boots, gauntlets,helmets,platelegs, chainmail, and platebody. And finally, most people would not want dual wielding weapons anyways (unless it was firearms).